Electronic circuits, and particularly computer and instrumentation circuits, have in recent years become increasingly powerful and fast. As circuit frequencies exceed several hundred megahertz (MHz), with the associated spectral components exceeding 10 gigahertz (GHz), noise in the DC power and ground lines increasingly becomes a problem. This noise can arise due to inductive and capacitive parasitics, for example, as is well known. To reduce such noise, capacitors known as decoupling capacitors are often used to provide a stable signal or stable supply of power to the circuitry. The decoupling capacitors are generally placed as close to the load as practical to increase their effectiveness.
Capacitors are further utilized to dampen power overshoot when an electronic device is powered up, and to dampen power droop when the electronic device begins using power, such as the immediate need for voltage caused by a processor performing a calculation.
Often, the capacitors are surface mounted to the electronic device, such as a processor, or the package substrate on which it is mounted. Other solutions have involved the formation of a planar capacitor integrated on or embedded within a substrate, such as high-density interconnect (HDI) substrates and ceramic multilayer structures. As electronic devices continue to advance, there is an increasing need for higher levels of capacitance for decoupling and power dampening at reduced inductance levels.
At increasingly reduced device sizes and packing densities, available real estate for surface-mounted capacitors becomes a limiting factor. Furthermore, for planar capacitors, increasingly higher capacitance requirements require increasingly large surface area. This increases the risk of shorts or leakage, thus reducing device yield and increasing device reliability concerns.
As will be seen from the above concerns, there exists a need for alternative capacitance solutions in the fabrication and operation of electronic and integrated circuit devices.